Different parts of the AZ treated with polar auxin transport inhibitor were characterized by a specific pattern of expression of abscission-related genes. The relative transcript levels of LlBOP (blade-on-petiole) (A), LlIDL (inflorescence deficient in abscission) (B), LlHSL (HAESA-like) (C), and LlMPK6 (mitogen-activated protein kinase 6) (D) were investigated. A solution of 2,3,5-triiodobenzoic acid (TIBA, 0.05 mM in 0.05% Tween 20) or 0.05% Tween 20 solution was applied directly on the inactive flower abscission zone (AZ). Then, the tissue sections containing the AZ (≈1 mm below and ≈1 mm above) were dissected 4 h or 6 h after treatments and divided into a proximal (PROX) and a distal (DIST) part for further RNA isolation. Gene expression was examined using qPCR analysis. LlACT (actin) was used as an internal control for the normalization of gene expression. Values are presented as the mean of three biological replicates. Error bars indicate SEs. t-test: ** p < 0.01 and * p < 0.05, proximal versus distal part in the Tween 20-treated AZ for different times after application; aa
p < 0.01 and a
p < 0.05, TIBA-treated distal part versus Tween 20-treated distal part for different times after application; bb
p < 0.01 and b
p < 0.05, TIBA-treated proximal part versus Tween 20-treated proximal part for different times after application.